A. Field of the Invention
This invention relates to a automobile-carrying trailer for transporting vehicles and particularly to control of loading of the trailer.
B. Background Art
It is conventional to transport motor vehicles upon open trailers. Usually several vehicles are positioned upon one trailer, several vehicles on a lower deck and several vehicles upon an upper deck. The decks are formed of ramps which may be controlled by hydraulic cylinders. The hydraulic cylinders have been controlled by hydraulic valves which were mechanically actuated by the operator manually, as well as by electrohydraulic valves which were actuated by an operator by means of electrical switches
In the prior art, as each vehicle was loaded upon the trailer, the operator adjusted the positions of the ramps to obtain an optimum position for receiving additional cars. In this manner, the most efficient positions for the ramps were obtained thereby maximizing the number of cars that could be loaded into the trailer and minimizing the likelihood of damage from vehicles being hit by a ramp or another vehicle.
This loading was extremely time consuming and was sometimes the occasion for accidental damage to the car.
The mechanical valves were operated by levers which manually shifted hydraulic valve spools. However, because hydraulic lines had to be coupled to the levers, the levers could not be moved while loading cars onto the trailer to permit optimum viewing of the ramps and cars while the ramps were being moved. Thus, the cylinders and, as a result, the ramps were difficult to control with precision making the job of loading vehicles on the trailer more difficult and accident prone.
After loading of an open trailer, during transporting of vehicles, the vehicles were subject to damage because they were exposed to the elements, flying objects and vandalism. Therefore, enclosed trailers were developed to protect the cars.
Since the vehicles on an enclosed trailer and the ramps had to be viewed from many directions and many angles in order to pack the vehicles as closely together as possible while not damaging them, a plurality of control units were located at different locations around the trailer. For example, an enclosed trailer had three different units located at the front, the middle, and the rear of the trailer. This resulted in extra requirements for cables and still required that the operator sometimes leave the controls, view the vehicles and the ramps, and return to the controls and operate them without actually being in the best position for viewing the result of the operation.